Insects and other arthropods constitute well over half of the living animal species on earth; they are important not only from a biological point of view, but also as disease vectors, as well as agricultural, forest, and household pests. Insects interact chemically with one another, with plants, and with predator enemies. The substances responsible for these interactions (i.e. pheromones, when the interaction is intraspecific) can influence behavior and, in some instances, development. They vary from the simplest of organic compounds to compounds of considerable complexity. The aim of this project is to chemically characterize biologically active arthropod secretions mediating these interactions. Synthetic and biosynthetic studies will also be undertaken. The basic interest of the work will be to elucidate the natural chemical mechanisms operative in this area of chemical ecology. The research may also lead to new biochemically-based techniques for chemical control of insects.